Since its launch in 2002, the Gravity Recovery and Climate Experiment (GRACE) has been providing important new information about water mass movement among the oceans, continents, and cryosphere. In this paper, we review the applications of GRACE data to understanding non-tidal ocean mass variability, including progress in reducing errors in the raw GRACE data. We will review recent results on understanding variations in mean ocean mass on a global scale, changes on more local scales resulting from changing winds and ocean transports, and also summarize progress on using GRACE data in ocean models. Such a synthesis of studies is important for quantifying what we have learned about ocean dynamics from the current gravimetry missions, what we still do not understand, and what needs to be improved in future satellite gravimetry missions.